Sulfamates of various structures, including those derived from monosaccharides, are described in J. Med. Chem. 1987, 30, 880 and in U.S. Pat. No. 4,075,351. Certain of these sulfamates are useful as pharmaceutical agents. More recently, sulfamates having various pharmaceutical activity in the areas of epilepsy, glaucoma, peptic ulcers, and male infertility are described in U.S. Pat. Nos. 4,513,006, 4,459,601 and 4,792,569. One of the compounds covered by U.S. Pat. No. 4,513,006, topiramate, has not only been found to exhibit particularly significant anticonvulsant activity in animals, but also appears to be useful in humans for the treatment of epilepsy (see Drugs Future, 1989, 14, 342). Still other related sulfamates are disclosed in a recently filed application (Ser. No. 07/874,875) by the same assignee as the present invention, which application was filed on Apr. 28, 1992.
While sulfamate compounds of the type disclosed in U.S. Pat. No. 4,513,006 have been shown to exhibit useful biological activity when administered to mammals, improved activity is desirable.
Accordingly, it is one of the objects of the present invention to describe novel derivatives of the sulfamate compounds of the type disclosed in U.S. Pat. No. 4,513,006 in which the sulfamate portion is masked by an imidate group that can be removed in a physiological milieu to generate the parent drug (See J. Med. Chem. 1988, 31, 2066). Such derivatives, known commonly as prodrugs, could afford improved biological activity or properties upon administration to mammals.